This project combines the research efforts of Z01-HG000113, Z01-HG000124, Z01-HG000127 and Z01-HG000129 into a single theoretical project focused on the development of new methodology for the statistical genetic analysis of quantitative traits. During the past year work has continued on the development of a method that can be used to accurately measure the heritability attributable to specific single locus effects (ROMP). This method is being used in several ongoing collaborative projects. Work has also focused on the development of a new method that can be used to empirically estimate the type I error rate in genomic screening data without performing extensive simulations or theoretical approximations. This method uses the existing family structure and marker characteristics to obtain an appropriate estimate of the type I error rate of the genomic screen. An abstract of this work has been accepted as a platform presentation at this year's International Genetic Epidemiology Society meeting. Other efforts include the development of a new method to measure the consistency of the estimates of heritability in longitudinal studies, evaluation of the variance components method under different ascertainment schemes (formerly HG000113), the use of single nucleotide polymorphisms (SNPs) as an alternative for micro-satellite markers in linkage analysis (formerly HG-000124), and the use of moving averages and clustered markers as an alternative to multi-point linkage analysis (formerly HG-000129).